Mathematical Obscurities in Special Relativity

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by kc3mx</i>
<br />The problem is to devise an experiment which differentiates the predictions of the two different theories. This has not been done.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">It was done in 2002 with our paper: “Experimental Repeal of the Speed Limit for Gravitational, Electrodynamic, and Quantum Field Interactions”, T. Van Flandern and J.P. Vigier, Found.Phys. 32(#7), 1031-1068 (2002).

The short story is that nothing (including Sagnac) in the light-speed or slower domain can distinguish the two models, SR and LR. However, something propagating FTL <i>in forward time</i> is impossible in SR but is routine in LR. So our demonstration that gravity propagates FTL in forward time falsifies SR in favor of LR -- a result now published in a major peer-reviewed journal of record. -|Tom|-

Tom, maybe you can tell me something. Why is the fact that light-speed can slow down in a gravity field such a secret in physics and astronomy today? I find it mentioned in a few papers, but on most websites and in most books, astronomers and physicists pretend light-speed is always “constant”.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by DAVID</i>
<br />Tom, maybe you can tell me something. Why is the fact that light-speed can slow down in a gravity field such a secret in physics and astronomy today? I find it mentioned in a few papers, but on most websites and in most books, astronomers and physicists pretend light-speed is always “constant”.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Everyone agrees light can slow down. It has even been "stopped" in one experiment. But according to SR, the speed of light <i>in vacuuo</i> is a constant. Light slowing in gravitational potential fields is usually not emphasized just to avoid having to explain why this is not in conflict with SR.

Of course, GR does have an explanation for this. In a gravitational potential, the observer's proper time and clocks slow down. So to that observer, the speed of light doesn't "really" slow when measured by the observer's slow clocks. But to the rest of us with a "God's eye" view, it does. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
<br />Everyone agrees light can slow down. <br /><hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

No they don’t. I have physicists and professional astronomers tell me all the time, on science message boards, that light never slows down. So what’s going on with these guys? Why do they deny it, and why do they turn red and blue in the face when I say that light-speed slows down in a gravity field?

In SR, the speed of light was “postulated” to never slow down, but in the 1911 gravitational redshift theory Einstein admitted that it slowed down, and in his 1916 book he said that the speed of light “varies with position”.

In the 1960s, Shapiro observed that the speed of his radar waves reflected off Venus slowed down when they passed the sun, and he’s not God.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by DAVID</i>
<br />I have physicists and professional astronomers tell me all the time, on science message boards, that light never slows down.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Now you have reduced this to a semantic issue. Every student is taught in elementary physics that the speed of light is air, water, or glass is substantially slower than its speed in a vacuum. In recent laboratorty experiments, light's speed was reduced to a mere 17 m/s.

What you are quoting, whether you realize it or not, is the distinction that Feynman taught us. Feynman said that light never really "slows down". Instead, all material mediums consist of atoms in a vacuum. Then the speed of light is c in the vacuum, when it makes progress. And the speed of light is zero while it is absorbed by atoms, then re-emitted after typically a 10 ns delay. So slowed light only <i>appears</i> slower because of all the absorption delays in any material medium.

But that is a very different matter than the one I thought you were asking about.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">So what’s going on with these guys? Why do they deny it, and why do they turn red and blue in the face when I say that light-speed slows down in a gravity field?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">If one believes in a theory, almost any phenomenon can be "explained" by introducing ad hoc assumptions. People who are persuaded by some belief tend to forget about Occam's Razor (the simplest explanation is to be preferred), and the need for continual testing of hypotheses with controls against bias in place.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">In the 1960s, Shapiro observed that the speed of his radar waves reflected off Venus slowed down when they passed the sun, and he’s not God.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Your reality and mine is that the speed of light does slow down. I thought you were asking why mainstream physicists maintain that it doesn't. The Feynman idea explains "slowing" in ordinary substances as delays, not real slowing. And GR explains the slowing of radar beams as an illusory slowing in coordinate time, that disappears when one measures with clocks traveling along with the radar beam ("proper time" clocks). So GR also has a rationalization to maintain the belief that light does not slow.

It's no use complaining about this. It is that way with all mainstream theories. There's an explanation available to allow maintaining any favored belief.

It's a good lesson in how <i>not</i> to do science for all would-be theorists. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>What you are quoting, whether you realize it or not, is the distinction that Feynman taught us. Feynman said that light never really "slows down". Instead, all material mediums consist of atoms in a vacuum. Then the speed of light is c in the vacuum, when it makes progress. And the speed of light is zero while it is absorbed by atoms, then re-emitted after typically a 10 ns delay. <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I’m not talking about light slowing down in glass or water. I never mentioned that. I’m talking about light slowing down in a vacuum. I never mentioned glass or water.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>

If one believes in a theory, almost any phenomenon can be "explained" by introducing ad hoc assumptions. People who are persuaded by some belief tend to forget about Occam's Razor (the simplest explanation is to be preferred), and the need for continual testing of hypotheses with controls against bias in place.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">In the 1960s, Shapiro observed that the speed of his radar waves reflected off Venus slowed down when they passed the sun, and he’s not God.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Your reality and mine is that the speed of light does slow down. I thought you were asking why mainstream physicists maintain that it doesn't. The Feynman idea explains "slowing" in ordinary substances as delays, not real slowing. And GR explains the slowing of radar beams as an illusory slowing in coordinate time, that disappears when one measures with clocks traveling along with the radar beam ("proper time" clocks). So GR also has a rationalization to maintain the belief that light does not slow.

It's no use complaining about this. It is that way with all mainstream theories. There's an explanation available to allow maintaining any favored belief.

It's a good lesson in how <i>not</i> to do science for all would-be theorists. -|Tom|-
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I'm not talking about slowing in "substances".

I’ve talked to professors and US government physicists on the internet (not necessarily the “best” ones available), and they feed me a lot of baloney about “curved space-time” at the sun, blah, blah, blah. The fact is, Shapiro observed the speed of the waves to slow down when they passed the sun. Even in Einstein’s 1911 theory, that’s the reason he gives for the bending of light at the sun. He even included a diagram in his paper.

Forget about “clocks traveling along with the radar beam”. That’s nonsense. Shapiro’s clock didn’t travel along with any radar beam. We don’t have to introduce a bunch of artificial thought experiments into this, such as clocks traveling with the beam. It’s a simple phenomenon. Light slows down in a gravity field. Einstein deduced this is 1911 and he repeated it again in 1916. There is no reason to complicate the issue or to try to mystify it, just so people can preserve the artificial and incorrect myth of the “constancy” postulate of the 1905 SR theory.